The invention relates generally to a lining for a furnace chamber and more particularly a lining stucture for such a chamber, which is at least approximately round in cross-section.
It is known for the lining of a furnace chamber to be subdivided into at least two layers in the radial direction, and at least two portions in the axial direction, with a seal of metal material as a gas seal therebetween.
Generally, the layers of such lining arrangements are made from different materials which are suitably selected in accordance with the temperature loadings and the thermal expansion phenomena to be expected in the respective layers in question. A gas seal arrangement, also referred to as a gas barrier means, may be provided between the axially separated portions of such a lining, in order to ensure that pressure differences within the furnace chamber do not cause gas to flow in an uncontrolled manner into rearward or outer layers of the lining, thereby causing damage to the lining. Such damage may be caused mechanically, as by the formation of passages or channels or other cavities in the lining or between the layers or portions thereof. It is also possible however to conceive of damage being caused by a chemical reaction.
When metal sheet or plate is used to form the gas seal, it has been found that difficulties often still occur, which are attributable to the fact that the metal sheets or plates have different coefficients of thermal expansion from the layers of the lining, which are generally formed by ceramic material. The difference in thermal expansion may cause the metal plates to be subjected to such a severe loading that buckling occurs or cracks are formed, so that the gas seal quickly becomes ineffective as a result. Generally, such cracks are found in the transitional region between two adjacent layers of the lining.
Hitherto, the above-described gas seals made from metal plates were in one piece in a horizontal or radial direction. For that reason, it was not possible, or it was possible only to a limited and therefore unsatisfactory extent, for differences in thermal expansion in the individual layers of the furnace lining to be compensated in the axial direction, in the region of the gas seal. Further disadvantages with such gas seals, being integral in a radial direction, are that it is difficult to replace for example only the inner layer of the lining and/or it is not possible to replace only part of the gas seal, for example in a region which had suffered damage.